I change my alternator and it's still not staying charged on 1998 Cadillac DeVille

While I'm driving the lights go out the car will stall in the battery will die

by in Chicago, IL on March 25, 2013
3 answers
ANSWER by on March 26, 2013
test alternator by starting engine and disconnecting neg. if car remains running then not your alternator. check your battery. maybe do for new one. rec. deep cycle for replacement. possible too if any mod.s made to sound system(upgrades may be drawing to much power for alt. to keep up with demand. run diagnostic for any other electrical issues you need to be aware of.
ANSWER by on March 26, 2013
Charge battery, start engine put lights on hi beam with heater on high. Check voltage at battery with a VOLT METER should be between 13 to 14.5 volts! Or have a repair shop do this it for you if you dont have a tester! Only way to tell how much alt. output actually is with no damage to system.
ANSWER by on March 26, 2013
double ck alt performance to start with then load test battery